As a result of the recent developments in medical techniques and the general medical care of hearts, a number of serious and mild cardiac diseases have been discovered and aided by cardiac therapy. However, mild cardiac patients, particularly cardiac sick infants discovered at the school by cardiac examinations conducted nationwide have been prevented from swimming as being too severe as exercise.
In conventional infant circulatory organ science, the reason that the mild cardiac infant cannot swim safely is the result of consideration of the energy consumption and the result of inspection of an electrocardiogram of the infants on the ground. So far, there has been no electrode for recording the electrocardiogram during swimming. Therefore, the swimming restrictions are not based on the results of the inspection of an electrocardiogram recorded during actual swimming.
However, the circulatory action during swimming is different from that during the exercises on the ground, and abnormal variations are observed during swimming. On the other hand, at present, since accurate circulatory action of a pupil during swimming is unknown, the safety of the mild cardiac sick pupil cannot be confirmed. It is diffucult to give approval for swimming to the mild cardiac sick pupil, based on a conventional inspection.
Consequently, it becomes necessary to prove that the pupil can swim safely based on an electrocardiogram recorded during actual swimming.
In order to record the electrocardiogram of a living body during swimming, it is necessary to put the electrodes on the skin surface of the pupil's body, to connect the electrodes through cables to an electrocardiograph placed on the ground, to let pupil with the electrodes swim, to lead ultrafine current from a heart induced on the skin surface during swimming through the cable to the electrocardiograph placed on the ground, and to measure the variation in the potential generated in the living body by the electrocardiograph.
In case that the electrocardiogram of the living body during swimming is recorded by the electrocardiograph placed on the ground as described above, when the living body swims for a long distance, the cable must be lengthened in response to the swimming distance. As the cable becomes longer, the cost increases, and further, an accurate electrocardiogram cannot be obtained due to leakage of the ultrafine current. Further, there is a problem that the examinee cannot swim freely since the examinee's legs and arms may be caught by the cable.